Safety device for internal combustion engine



Jan. 7, 1969 P. R. POWELL ETAL 3,

SAFETY DEVICE FOR INTERNAL COMBUSTION ENGINE Filed July 31, 1967 FIG- 3 INVENTORS PAUL R. POWELL JOHN ROPER United States Patent 3,420,217 SAFETY DEVICE FOR INTERNAL COlVIBUSTION ENGINE Paul R. Powell, 518 Charles St. Ave., Towson, Md. 21204, and John Roper, 1325 Eutau Place, Baltimore, Md. 21217 Filed July 31, 1967, Ser. No. 657,227 US. Cl. 123-198 Int. Cl. F22b 37/47; F02 77/08 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the same subject matter as the application for Letters Patent for Combustion Engine Temperature Protection Ser No. 588,453 filed October 21, 1966, now Patent 3,385,940. This application relates to a modified form of the invention, that is, it pertains to the protection of combustion engines from becoming overheated.

In general, the device is designated by the numberal and dependent on an alloy that melts at a predetermined temperature. The failure of the alloy to withstand such temperatures insures protection to the engine from overheating. This temperature for the melting point of the alloy has been found by experiment to be approximately 240 F. When the alloy 3 melts it breaks the electric circuit to the pump 13 furnishing fuel to the engine and/or in a gas operated engine, it breaks the circuit to an electric circuit upon which the function of the engine depends, such as the circuit to the ignition system, whereby the engine stops.

In detail, the alloy 3 is a link in the electric circuit operating a pump 13 or a similar device that supplies the engine with fuel, or is connected in the ignition supply line of a gas engine. When the alloy melts, the circuit is broken, stopping the engine.

In more detail, a plug 6 is provided to contain the elements necessary to cause this unit to function as a fail-safe-plug.

FIGURE 1 shows the switch in closed positoin.

FIGURE 2 shows the switch in open position.

FIGURE 3 shows the switch in an engine accessory circuit.

Reference to drawings, FIG. 1 is a fragmentary sectional view of the fail-safe-plug installed in the water or liquid cooling jacket of the cylinder head 1.

A pin 2 is secured to the plug 6 and is held in place by the alloy 3. The pin 2 is under tension from a spring 3,420,217 Patented Jan. 7, 1969 4. The knob '5, preferably of plastic, is an electric insulator and is threadably receivable on the pin and is preferably provided with a lateral hole 5 to accommodate an insulated wire 22. In the present installation the wire 22 is connected to the ground side of the unit 20 which is shown in FIG. 3 as a pump 13 or it may run to the ground side of the ignition system, as the case may be. The insulation 22' of the wire 22 is removed adjacent the end of the wire and the wire is inserted in the hole 5' of the knob 5, after which the knob is advanced on the threaded pin 2 securing the wire between the upper side of the hole and the top of the pin 2 as shown in FIGS. 1 and 2.

During the normal operation, the plug 6 is covered by the liquid 21 in the cooling system and is at a temperature of say F. If and when, due to the loss of the cooling liquid while the engine is in operation, the cylinder head 1 undergoes a rapid rise in temperature, the alloy will melt, releasing the pin 2, which will disconnect the electric circuit. The cylinder head 1 is most sensitive to the heat generated by the combustion of the fuel, therefore, the first abnormal heat in cylinder head 1 is conducted to plug 6, then passed on to alloy 3. When alloy 3 reaches 240 F. the alloy melts; releasing the compression spring 4 and forcing the pin 2 outwardly to break the electric circuit as shown in FIG. 2 before damage or dstructi-on of the engine from further over-heating takes place.

The wire 22 will support the pin knob 5 and the spring 4 after the alloy has melted, as shown in FIGURE 2. The dangling of the elements after the melting of the alloy may be readily observed as a signal or tell-tale of the loss of liquid from the cooling jacket causing the engine to become overheated.

FIGURE 3 is an electrical diagram generally referred to by the numeral 20 illustrating a re-starting emergency circuit that provides the operator with a control to safely park the vehicle. When the temperature has caused the alloy to melt and to disconnect the electric circuit, a spring loaded switch 8 is provided in reach of the operator which may be operated to close the electric circuit temporarily by physically holding the switch in closed position. The operator employs one hand to overcome the spring tension 8 establishing the electric circuit from source 9 through wire 22 in order that the ignition may be operated. The operator restarts the engine with the other hand. With the engine running one hand is now free to park the vehicle while the other hand must be employed to tend the emergency spring loaded switch 8. As soon as safely parked, the operator releases spring loaded switch 8 which breaks the electric circuit stopping the engine.

What is claimed is:

1. A safety device for internal combustion engines including a combustion chamber and a jacket surrounding said chamber for retaining a liquid coolant comprismg:

(a) a base element of electrically conductive material adapted to be fixed to the said jacket;

('b) a pin of electrically conductive material having one end fixed to the base element by a fusible material having a pre-determined temperature melting point;

(c) an electrically operated mechanism in cooperation with a fuel supply assembly for operating said engine,

said assembly having suitable electric conduits leadreleased by the melting alloy from the said base element. ing to the assembly for operating the same; 7

(d) a cap of non-electrical conductive material en- References Cited tgagzi'ble Withdthc: Opposite enc offstziid plin adagte? UNITED STATES PATENTS ocampsal pinooneen o eeecr1cconu1;

(e) an expandable element positioned between the g s; base element and the cap for separating the cap 1 646835 10/1927 g 2%:142 and pin from the base upon the melting of the fusible 2149773 3/1939 er 200 142 material, thereby breaking the electric operating 2442830 6/1948 p g fiz 200 142 circuit to the assembly.

2. In a safety device for internal combustion engines 10 g -B et as claimed in claim 1 wherein the fuel supply assembly oper comprises a fuel injection pump.

3. In a safety device for internal combustion engines WE L fi SF m' 'l as claimed in claim 1 wherein the expandable element 15 US Cl comprises a guard to prevent the electrically charged 337;107 408 409 pin from making a ground contact after it has been 

